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OpenLayers Cookbook

OpenLayers Cookbook

4.8 (9)
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OpenLayers Cookbook

OpenLayers Cookbook

4.8 (9)

Overview of this book

Data visualization and analysis has become an important task for many companies. Understanding the basic concepts of GIS and knowing how to visualize data on a map is a required ability for many professionals today. OpenLayers is a JavaScript library to load, display, and render maps from multiple sources on web pages."OpenLayers Cookbook" teaches how to work with OpenLayers, one of the most important and complete open source JavaScript libraries.Through an extensive set of recipes, this book shows how to work with the main concepts required to build a GIS web applicationñ maps, raster and vector layers, styling, theming, and so on."OpenLayers Cookbook" includes problem solving and how-to recipes for the most common and important tasks. A wide range of topics are covered.The range of recipes includes: creating basic maps, working with raster and vector layers, understanding events and working with main controls, reading features from different data sources, styling features, and understanding the underlying architecture."OpenLayers Cookbook" describes solutions and optimizations to problems commonly found.
Table of Contents (15 chapters)
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OpenLayers Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Buffering the layer data to improve the map navigation


Map navigation is an important factor to take into account to make the user experience better.

When we pan the map, many times we get to see blank areas (meaning that the content is loading) and after a few seconds the image appears.

On gridded layers and WMS layers working in single tile mode, we can improve this at the cost of increasing the requests number or increasing the computation time at the server side.

Note

Most of the raster layers inherit from the base class OpenLayers.Layer.Grid, which is responsible for dividing each zoom level into tiles.

For WMS layers working in single tile mode, the grid is formed only by one tile, which fills the whole map view.

The idea behind improving map navigation is simple; load the tiles outside the map view so that they are loaded before the user pans the map view in that direction.

This recipe shows you how to preload content outside the map view, both for gridded layers and also for WMS layers...

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